Speedometer driving mechanism



Jan.- 9, 1923.

SPEen'czmla-l-ER DRIVING MEcHAN l sM. FILED JAN. 30. 1922' f 1,441,471l T. o. ADAIR, JR.

- 55 Zn/venian' A am@ Ik WM/fW/M-f Patented Jan. 9, 1923.

UNITED STATES PATENT OFFICE.

THOMAS DONALD ADAIR, JR., OF DORCHESTER, MASSACHUSETTS, ASSIGNOR TO STANDARD THERMOMETER COMPANY, OF ROXBURY, BOSTON, MASSACHU- SETTS, A CORPORATION OF MAINE.

SPEEDOMETER DRIVING MECHANISM.

Application led January 30, 1922. Serial No. 532,637.

To al] whom t muy concern.'

Be it known that I, 'lI-IoMAs DoNALo Amm, .l r.. a citizen of the United States. residing at Dorchester, in the county of Suffolk and State of Massachusetts, have iny and use the same.

The present' invention relates to an improvement in speedometer driving mechanism.

The object of the invention is to reorganiZe and improve speedometer driving mechanism for the purpose of simplifying its construction, improving wearing conditions, and rendering it less expensive. To the above ends the present invention consists in the speedometer drivingr mechanism hereinafter described and particularly defined in the claims.

In the accompanying drawings illustrating the preferred form of the invention, F ig. 1 is a sectional longitudinal elevation of a portion of the transmission gearing, taken on the line 1-1, Fig. 2; Fig. 2 is a section taken on the line 2 2, Fig. 1 and Fig. 3 is a detail hereinafter referred to.

The illustrated embodiment is described as follows: The transmission housing 10 carries the bearing 11 which supports the rear end of the driving shaft 12. The driving shaft 12 is squared at 13, and carries on its end the coupling plate 14 by which the` driving shaft is connected in the usual manner to the propeller shaft. T he coupling plate 14 is secured to the driving shaft by the nut 15, which is screwed on the reduced portion 16 on the end of the shaft. a washer 17 being interposed between the nut and the shoulder 18 on the coupling plate. The

driving shaft also carries on its squared por.

tion a worm 19. A spacer ring 20 between the worm and the bearing 11 holds the worm in correct longitudinal position on the driving shaft. The supplemental housing 21 encloses the worm 19 and is provided With a gasket 22, which engages the outside surface of the hub 23 of the coupling plate 14, thereby preventing ingress of dirt and egress of oil and grease. The Worm 19 meshes with the other construction above described.

a worm wheel 24. This worm wheel is being driven by the worm 19, rotates at a certain speed in relation thereto, and constitutes the member from which the speedometer drive shaft is driven. This worm wheel 24 is provided with a bearing portion or stem 25, which is received in a bearing 2G in the supplemental housing 21. This mode of support of the worm wheel 24 affords a good substantial bearing for the worm wheel, holds it in correct.position in relation to the worm at all times, and provides etlicient lubrication. The worm wheel is provided with a longitudinal bore 27 having a key-way 28 to receive the speedometer connecting stem 29 to the speedometer drive shaft 30. The stem 29 is provided with the usual key 31, which engages the key-way 28. The speedometer drive shaft 3() is incased in the casing 32 to the end of which is attached the plug 33, which has a screw-threaded portion adapted to be received in the screw-threaded hole 34 in the supplemental housing. The end 35 of the plug 33 projects toward and approximates in position the surface of the worm wheel 2-1 so that the worm wheel is held in its bearing by the plug 33.

In Fig. 3 is shown a modified form of plug 40, with a similar threaded portion 41. which is screwed into thel hole 34 in the supplemental housing 21, the end of which extends to the surface of the worm wheel as in The outer end 42 of the plug is screw-threaded. and the casing 32 of the flexible driving shaft. is provided with the usual flange ring 43 by which the casing is attached to the plug 4() by means of they gland 44.

It will be observed that in the construction illustrated in Figs. 1 and 2. the speedometer drive shaft, its case and plug, may be removed from the supplemental housing by detaching it first at the speedometer. and then unscrewing the plug 33 and withdrawing it from the housing. In the construction shown in Fig. 3. the speedometer drive shaft may be removed by unscrewing the gland 44 of the supplemental housing, which releases the casing from the plug 42, whereupon the driving shaft may be pulled out of the worm Wheel without removal of the plug 40.

In both constructions the worm Wheel, by

which the speedometer shaft is driven, is Well supported in ample bearings and provided with good lubrication. The adequate support of the Worm shaft secures the accurate engagement of the Worm wheel with the Worm.

`When it is desired to dismantle the construction, the supplemental housing may be removed from the transmission casing, carrying With it the bearing and associated parts. By removal of the nut 15 the coupling plate 14 may be pressed off the shaft, whereupon the Worm 19 may be slid of.

While the present mechanism is described in this specification and in the claims as a speedometer driving mechanism, it is to be understood that the invention is. not limited to speedometer driving contrivances, as it is equally adapted for transmitting power to an odometer or to other travel indicating devices.

Having thus described the invention, what is claimed is:

1. Speedometer driving mechanism having, in combination, a transmission housing, a driving shaft in said housing, a supplemental housing, the driving shaft extending from the transmission casing through the supplemental housing, a Worm secured to the driving shaft Within the supplemental housing, a Worm Wheel provided with a-bearing shank, and a speedometer drive shaft connected with the Worm Wheel, said supplemental housing being provided with a drive shaft hole through which the speedometer drive shaft loosely'enters and with a bearing opposite the hole to receive the bearing shank of the Worm Wheel.

2. VSpeedometer driving mechanism having, in combination, transmission mechanism, a supplemental housing provided With a bearing, a driving shaft in the transmission casing extending into the supplemental housing provided with a Worm, a worm Wheel provided with a bearing portion supported directly in the bearing in the supplemental housing, said housing being provided' with a hole through which the Worm Wheel may be introduced into the bearing in said housing, a plug for closing the hole, a speedometer drive shaft, said plug being provided with a longitudinal bore of larger size than the drive shaft and a casing for the drive shaft, the drive shaft being connected with the Worm v vheel, and the casing being connected with the plug.

speedometer driving mechanism having. in combination, .a transmission case, a supplemental housing, a driving shaft mounted in the transmission case and eX- tended into the supplemental housing, a

ivorm secured to the driving shaft within the supplemental housing, a Worm Wheel provided With a bearing portion extending from one side thereof and with a longitudinal bore provided With a keyway entering from the other side and extending Within the bearing portion, a speedometer drive shaft provided With a key adapted to be received in the longitudinal bore of the Worm Wheel, said supplemental housing being provided With a Worm Wheel bearing for the bearing portion of the Worm Wheel and with an opening through which the speedometer drive shaft enters the housing.

4. ySpeedometer driving mechanism having, in combination, a transmission case, a supplemental housing, a driving shaft mounted in the transmission case and eX- tended into the supplemental housing, a Worm secured to the driving shaft within the supplemental housing, and a Worm Wheel provided With a long bearing portion onv one side thereof, said supplemental housing being provided with a bearing for the bearing portion of the worm Wheel located in the bottom portion of the supplemental housing, so that the lubricant may ioW thereto by gravity.

5. Speedometer driving mechanism having, in combination, a transmission case, a supplemental housing, a driving shaft mounted in the transmission case and extended into the supplemental housing, a Worm secured to the driving shaftwithin the supplemental housing, and a Worm Wheel provided with a long bearing portion on one side thereof, said supplemental housing being provided with a bearing to receive the bearing portion of the Worm Wheel, and said bearing portion of the worm wheel being provided With a longitudinal bore opening on the opposite side of the Worm Wheel from the bearing portion adapted to receive the s eedometer drive shaft stem.

6. peedometer driving mechanism having, in combination, a transmission case, a supplemental housing, a drive shaft mounted in the transmission case and extended into the supplemental housing, a Worm secured to the driving shaft Within the supplemental housing, a Worm Wheel provided with a long bearing portion on one side thereof, said supplemental housing being provided With a bearing for the bearing portion of the worm Wheel, and a speedome- 'ter drive shaft, said Worm wheel and drive shaft being provided with driving connections on the s1de of the Worm wheel opposite the bearing portion.

T. DONALD Anais, JR. 

